[Article Review] Hidden Harm: Prenatal Phthalate Exposure and Its Impact on Young Brains

Reference

Ghassabian, A., van den Dries, M., Trasande, L., Lamballais, S., Spaan, S., Martinez-Moral, M-P., ... Guxens, M. (2023). Prenatal exposure to common plasticizers: a longitudinal study on phthalates, brain volumetric measures, and IQ in youth. Molecular Psychiatry. https://doi.org/10.1038/s41380-023-02225-6

Review

The paper by Ghassabian et al. (2023) explores the under-researched area of prenatal phthalate exposure, specifically its associations with brain volumetric differences and cognitive development in youth. Drawing from a cohort of 775 mother-child pairs from the Generation R study, the authors leveraged both prenatal maternal urine phthalate levels and subsequent T1-weighted MRI scans of the children at age 10. They aimed to establish correlations between prenatal phthalate exposure and brain volume and to explore if these brain measures mediated an association with IQ levels at age 14.

Findings reveal that higher maternal concentrations of monoethyl phthalate (mEP) during pregnancy were linked to smaller total gray matter volumes in 10-year-old offspring. Notably, these volume differences partially mediated the connection between higher mEP levels and lower child IQ, accounting for 18% of the effect. Gender-specific effects were also reported; in girls, there was an association of higher monoisobutyl phthalate (mIBP) with decreased cerebral white matter volumes, which mediated the link between increased mIBP and reduced IQ. These results underscore the potential neurotoxic effects of phthalates on developing brains, signaling alarm for their ubiquitous presence in consumer products.

While this research paves the way for understanding the neurodevelopmental implications of phthalates, there are aspects to consider for future studies. Primarily, the question arises on potential confounding variables, such as socio-economic status or other environmental factors, that might influence the observed associations. Furthermore, exploring potential mechanisms behind these observed changes would provide deeper insight. Notwithstanding, Ghassabian et al.'s study shines a light on the pressing need to re-evaluate and potentially regulate the use of phthalates in consumer products.

[Article Review] The Burden of Early-life Chemical Exposure on Neurodevelopmental Disabilities in the US

Reference

Gaylord, A., Osborne, G., Ghassabian, A., Malits, J., Attina, T., & Trasande, L. (2020). Trends in neurodevelopmental disability burden due to early life chemical exposure in the USA from 2001 to 2016: A population-based disease burden and cost analysis. Molecular and Cellular Endocrinology, 502, 110666. https://doi.org/10.1016/j.mce.2019.110666

Review

The study by Gaylord et al. (2020) aimed to quantify the burden of neurodevelopmental disability and the economic costs associated with early-life exposure to endocrine-disrupting chemicals (EDCs) in the United States from 2001 to 2016. Using data from the National Health and Nutrition Examination Surveys, the authors estimated the intellectual disability (ID) burden attributable to in-utero exposure to polybrominated diphenyl ethers (PBDEs), organophosphates, methylmercury, and early-life exposure to lead. They also calculated the economic costs of the IQ point lost and cases of intellectual disability. The results showed that PBDE exposure was the most significant contributor to the ID burden, resulting in a total of 162 million IQ points lost and over 738,000 cases of intellectual disability. Lead, organophosphates, and methylmercury were the other contributors. Although most of the trends showed improvement in children's neurodevelopmental health, they also indicated the use of potentially harmful chemical substitutions for those being phased out.

The findings of this study have significant implications for public health policies and regulations regarding the use and exposure of EDCs. The authors suggest that current regulations on EDCs should be strengthened to reduce the burden of neurodevelopmental disabilities and the associated economic costs. The study also highlights the need for continued monitoring of trends in early-life chemical exposure to ensure that the use of potentially harmful chemicals is adequately controlled. Limitations of the study include the use of cross-sectional data and the lack of information on exposure to other chemicals known to cause neurotoxicity. However, the study provides valuable insights into the burden of neurodevelopmental disabilities and the costs associated with exposure to EDCs in the US.